It might be smarter to charm one of the melee riders. Swords always beat bows once they close into melee, so if you converted an archer, you'd only succeed in getting him killed and maybe another. If you get a sword goblin, he'll be able to stab his potentially hostile wolf before it tears him apart (something that a bowman might not be able to do), AND run around killing his fellow bowmen.

Either way, I still think magic missile should come first. The faster we kill the bowmen, the more time and breathing room we have to handle the rest. Charming him will eventually get him killed too, but consider your options. You only have 1 hitpoint and 8 AC, so even one mistake will be your last. Hopefully 0 HP only means disabled and not dead, right?

Yeah, you are unconscious for an hour at 0 HP, and then get restored to 1 HP. At negative HP you must make Con checks every hour or lose 1d6 HP; success means you regain 1 HP. After three successful checks you are restored to 0 HP if you're still in the negatives. You die at HP equal to your negative (Level + Con). So Nisos would die at -6 HP.

I cut myself loose and position best for cover. Then I loose the bolt from Gerald's crossbow, at a bowman. If more bolts came with it, I'll reload after. If not, I prepare my dagger and look for better cover.

But the crossbow and quiver hit the branches and get stuck a bit away from Gregor. Gerald focuses on keeping any enemy from crossing the circle of fire. (Response action)

Adarim dips an arrow into the burning oil and fires it at one of the bowgoblins.

Rolled Ranged 17+1 vs. AC, rolled 4 damage

The goblin is hit in the chest and slides off its wolf with a dying gurgle.

Saucix lays a hand on Gerald's shoulder and speaks a prayer to Päkkaan.

Rolled healing 2+2 HP

The goblin arrow falls out of Gerald and his wound closes almost completely.

Nisos gets into cover as best he can, behind his comrades. He looks at one of the bowgoblins and speaks the words of arcane friendship.

Rolled Spell 15+4 vs. Will

The goblin realizes that Nisos is its greatest friend! And all these evil goblins are trying to kill him! Enraged, it lifts its bow and fires at one of the swordgoblins, hitting it in the arm. The struck goblin looks around at the traitor in confusion.

Gregor cuts himself loose and climbs over to Gerald's crossbow. He gets hold of that and the bolts, but can't shoot this turn.

The remaining bowgoblin fires an arrow at Gerald, but misses.

The swordsgoblin who was shot at by Nisos' friend charges the traitor. With a single swing it severs the bowgoblin's head from its shoulders.

The other three swordgoblins spur their wolves. They, as well as the wolf of the goblin that Adarim killed, charge forward, and try to leap across the flames. One of the ridden wolves makes it across unscathed. The lone wolf and another ridden wolf get singed. The last ridden wolf catches on fire!

Gerald takes a swing at the singed unridden wolf.

Rolled 3+2 vs. AC

The wolf dodges Gerald's sword. It retaliates, along with another wolf and goblin! But Gerald's armor keeps both teeth and swords at bay.

Another rider and its mount attacks Saucix. The goblin's sword misses, but the wolf bites the elf's leg. 2 damage

The burning wolf was leaping at Adarim, and now tumbles towards him in desperation. Adarim can't get out of the way fast enough, and gets burned. 2 damage

The riding goblin jumps off the burning wolf's back and lands in the snow, slightly scorched.

Opposition:(Outside the fire)1 goblin with short sword1 goblin with shortbow3 wolves, 1 of them unridden(Inside the fire)3 goblins with short swords, 1 of them on the ground4 wolves, 2 of them unridden, 1 of these burning

We can probably start focusing on melee at this point. Nisos and Gregor have a good chance to take out the bowman while remaining relatively safe. Either way, use your best attacks/weapons. I can't wait until Gregor gets an opportunity to backstab someone...